Table 1 Age and age-adjusted baseline characteristics of cancer-free women and breast cancer survivors in the BOSS cohort study

Age^b, years, mean (SD)

44.7 (11.3)

48.1 (10.3)

< 0.001

Race, white, %

88.7

83.3

0.02

Education, ≥ 4 years of college, %

77.6

77.4

0.72

Postmenopausal, %

27.4

51.6

< 0.001

Age at menopause^c, years, mean (SD)

49.6 (4.9)

48.8 (3.4)

0.86

Bilateral oophorectomy at age < 45 years^d, %

49.0

34.3

0.02

BMI, kg/m², mean (SD)

26.2 (5.1)

25.9 (3.1)

0.29

Physical activity, MET-h/wk^e, mean (SD)

29.4 (27.9)

26.0 (15.5)

0.29

Alcohol intake, g/d, mean (SD)

5.7 (7.5)

5.7 (4.8)

0.99

 Never

58.8

52.5

0.55

 Former

36.7

44.8

 Current

4.2

2.7

 Missing

0.3

0.0

HRT ever use, %

15.1

14.5

0.04

Ever mammogram^f, %

99.5

97.8

0.63

Ever pap smear, %

98.6

99.1

0.15

Current vitamin D supplement use, %

7.8

20.8

< 0.001

Current calcium supplement use, %

25.5

28.1

0.97

Bone density examination, %

28.9

43.0

0.02

Bone density examination in women aged ≥ 45 years, %

51.2

60.0

0.08

Ever broken bone, %

6.4

6.8

0.84

 No family history

14.7

38.9

< 0.001

 First-degree relative only

64.8

50.7

 First- and second-degree relatives

17.0

9.0

 Missing

3.5

1.4

 Negative

69.7

73.9

0.33

 Positive

27.3

19.4

 Variants of uncertain significance

2.9

6.7

Age at diagnosis, years, mean (SD)

–

46.8 (10.2)

–

Time from diagnosis to baseline, years, mean (SD)

–

1.4 (1.3)

–

Invasive breast cancer (stage I–III), %

–

82.5

–

Estrogen receptor status^h, %

–

–

 Positive

–

75.9

–

 Negative

–

23.6

–

 Missing/untested

–

< 1.0

–

HER2 status^h, %

–

–

 Positive

–

14.4

–

 Negative

–

81.6

–

 Missing/untested

–

3.5

–

Triple-negative status^h, %

–

19.0

–

Breast cancer treatment^i,j, %

–

–

 Surgery

–

100.0

–

 Chemotherapy

–

49.8

–

 Hormone therapy, any

–

65.4

–

 Hormone therapy, by type^k

–

–

  Tamoxifen

–

67.4

–

  Aromatase inhibitor

–

41.3

–